The present invention relates to an apparatus and method for displaying medical images of a sliced tissue in the body of a patient, and more particularly, relates to the apparatus and method for displaying modified forms of time-dependent image data obtained by dynamic scanning at the sliced tissue.
In conventional medical diagnoses, medical examinations using imaging methods such as X-ray computed tomography(CT), nuclear magnetic resonance(NMR), and nuclear medicine(NM) have been frequently carried out to obtain time-dependent image data at a lesion of a patient, the image data permitting a clearer understanding of diseases.
In examinations by the X-ray CT, for instance, a dynamic study has been widely known for detecting the time-dependent image data. The dynamic study is an up-to-date manner, in which the flow of contrast medium can be observed as a substitute for time-dependent information showing motion of blood vessels or organs after a bolus-injection of the medium into a lesion.
The dynamic study with the X-ray CT apparatus first includes a plurality of scanning processes. These scanning processes are carried out at a fixed slice position in the patient is body at a certain time interval after a single injection of contrast medium therein. A slicing tissue will be set to be parallel to the X-Y plane when the longitudinal axis of a patient is aligned with the Z axis of a Cartesian coordinate system. The scanning collects a plurality of two-dimensional (2-D) image data throughout the sliced tissue. Next, a region of interest(ROI) is designated by an operator at a desired position or an area(e.g., round-shaped or rectangular-shaped) on a display screen showing a sliced 2-D image. The area of the ROI is normally set to be rather small in order to maintain high accuracy for observation. A processor of the apparatus, then, calculates a mean value of the CT values within the each area corresponding to the ROI through all scanned 2-D image data. Finally, a profile(i.e., time-density curve) of the mean values is formed and visualized on the screen.
The dynamic study is able to show a profile about CT values qualitatively, but the profile covers only the area of the designated ROI. Then, for inspecting a generality of a doubtful lesion, if it is required to display the time-dependent profile or information with a longer or wider scope in comparison with the above narrow ROI, the operator has to repeat the above-described dynamic study with relocating the ROI. As a result, a diagnosis for one patient requires frequently cumbersome operations.